[Eeglablist] Critical pitfall of spectral power analysis?

[Daniele Marinazzo]

I think that there is a substantial flaw in that paper (and in many
approaches to the matter). 1/f can be generated by "pure oscillations" with
nonuniform amplitude, among other things, but I would say that amplitude
modulation is a primary cause. And this same phenomenon is the very reason
why we do time frequency analysis.
Of course we don't know the ground truth, and all the measures that we use
are measures of behavior rather than mechanism, leaving us with the burden
(and sometimes the arbitrariness) of the inference step.
So, in a world where 1/f, noise, oscillations are completely separated
things, the results in that paper could make sense. In my opinion, the real
world is different.

On Sat, 9 Aug 2025 at 19:59, 장진원 via eeglablist <eeglablist at sccn.ucsd.edu>
wrote:

> Hi all,
>
> Recently I found one interesting article that addresses the pitfall of
> baseline correction that many scientists have used to transform EEG to
> time-frequency domain. According to this article, power spectrum formation
> is highly exposed to subject-dependent noise that independently affects
> power spectrum regardless of signal. Because I am not an engineer who
> majors signal transformation, I wonder how eeglab could handle this issue
> in spectral power analysis because this article implies that using alpha
> (8-13Hz) or theta (4-8)Hz is totally unacceptable in clinical studies.
>
>
> Reference: Gyurkovics, M., Clements, G. M., Low, K. A., Fabiani, M., &
> Gratton, G. (2021). The impact of 1/f activity and baseline correction on
> the results and interpretation of time-frequency analyses of EEG/MEG data:
> A cautionary tale. NeuroImage, 237, 118192.
>
> https://urldefense.com/v3/__https://doi.org/10.1016/j.neuroimage.2021.118192__;!!Mih3wA!FUy2N9N5bZQJF1IM06-OIaXtDG8YvPWzfrSGxmJE6N_4DPqW9Irqgr9P4PajtadaJV9Jzo1Z9QWJsE2RPNZmbe-Mkw$
>
> Best regards,
> Jinwon Chang
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